HSP90: a rising star on the horizon of anticancer targets.

Over the past decade, heat-shock protein (HSP)90 has begun to draw increasing attention as a novel anticancer target with unique features. As a molecular chaperone, HSP90 promotes the maturation and maintains the stability of a large number of conformationally labile client proteins, most of which are involved in biologic processes that are often deranged within tumor cells, such as signal transduction, cell-cycle progression and apoptosis. As a result, and in contrast to other molecular targeted therapeutics, inhibitors of HSP90 achieve their promising anticancer activity through simultaneous disruption of many oncogenic substrates within cancer cells. This review provides a brief summary of HSP90 biology and its association with cancer. It describes the discovery and development of HSP90 inhibitors as anticancer agents and their current status in the clinic. Finally, it closes with a discussion of the unique challenges confronting the further development of these agents and their prospects for the future.